This MPG is why I bought the 3.21

[Wild one]

Lol…. Did I mention 99.9 mpg in a Ram truck. Hahaha

When you hit 100.0 then you got something to talk about,everybody hits 99.9 occassionally,but you're really special if you get it to say 100.0

 

[pacofortacos]

OK like someone said, you are a 3.21 "homer",....DUDE. I understand the profound effect confirmation bias is having on you here. I have no need to argue with you because I don't give a flip what you drive. However, you should know I have a very respectable technical background. You really are arguing with the wrong person right now. If you want to believe the 3.21 is the superior gearing, just because you bought it, have at it dude.

Depending on what you are doing the 3.21 can be the superior gearing, with other conditions the 3.92 can be the superior gearing.

Empty, stock and with cruise engaged at 70+ mph on the highway, the 3.21 will be superior to the 3.92 gears for mpg. Not even close. Most 3.92 rams get in the 17-18 mpg under those conditions, most 3.21 Rams will get 20-23 mpg. (4 WD CC trucks)

Now drop down to 45-50 mph back roads and the 3.92's shine there. Which strangely enough happens to be where the rpms are nice and low (8th gear) and almost similar to where the 3.21's are at 65-70 mph.

I have had to do extensive under body mods to get over 17 mpg @ 74 mph on cruise @ sea level and flat interstate with my 3.92's.
Of course you always have the handful of 3.92 equipped trucks that seem to get almost 3.21 mpg - but they are rather rare.

 

[Hookedup87]

Been running 87 for a while now as the fuel prices have been ridiculous. Starting to ease just a bit recently so the other day I filled it with 89, like I used to run. Actually I used to run 93 and have my Pulsar on Performance mode, but that’s another story.

Anyway, with that tank of 89, driving exactly the same way, looks like my average MPG picked up about a half a mile per gallon. Not that that’s gonna change my life in any way, but, I just found it interesting.

 

[ramffml]

Now drop down to 45-50 mph back roads and the 3.92's shine there. Which strangely enough happens to be where the rpms are nice and low (8th gear) and almost similar to where the 3.21's are at 65-70 mph.

There is no difference at 45 - 50. The exact same gear ratios are available in both trucks.

The 3.92 "shines" from a dead stop. That's it.

 

[Docwagon1776]

????

Hypermiling. The 'drive faster' parts are fun, but the 'drive slower'... Ick.

 

[Wild one]

Hypermiling. The 'drive faster' parts are fun, but the 'drive slower'... Ick.

Okay what in hell does "Ick" mean.

 

[2020PW]

Ick

 

[Docwagon1776]

Okay what in hell does "Ick" mean.

Definition of ick​

interjection
(used as an expression of distaste or repugnance.)

From root word icky:

adjective, ick·i·er, ick·i·est.Informal.
repulsive or distasteful.
excessively sweet or sentimental.
unsophisticated or old-fashioned.
sticky; viscid.

 

[pacofortacos]

There is no difference at 45 - 50. The exact same gear ratios are available in both trucks.

The 3.92 "shines" from a dead stop. That's it.

True, but at that speed the 3.92's are in 8th and just barely over idle - just a good overall experience with gentle 0-50 mph cruising. Granted you will will be at about the same rpms in 7 with the 3.21's, below 6th gear the spread between gears gets greater than 6-7-8. So you do have the plus of the extra gear with the small spread for going up hills, etc.

In normal empty driving the 3.92 is actually almost useless from a dead stop, I am out of 1st by 5 mph.

 

[Wild one]

True, but at that speed the 3.92's are in 8th and just barely over idle - just a good overall experience with gentle 0-50 mph cruising. Granted you will will be at about the same rpms in 7 with the 3.21's, below 6th gear the spread between gears gets greater than 6-7-8. So you do have the plus of the extra gear with the small spread for going up hills, etc.

In normal empty driving the 3.92 is actually almost useless from a dead stop, I am out of 1st by 5 mph.

3.21's will pull 8th at 50mph on flat ground if you're driving the truck for milege.Stand a quart jug or bottle up in the middle of the box,and drive so it doesn't slide around or tip over,and you'll be amazed at how much better the milege will be,lol. That was my dads training when i was learning to drive at 9 years old on the farm and back roads of Saskatchewan in the late 60's/early 70's,and it still applies to this day.

 

[Dodge 1500 4X4]

Also, with 3.92 gears the engine RPMs are much higher shifting through the gears from a dead stop, tell with the higher RPMs are you consuming more fuel, and are these higher RPM's good for the engine? I know everyone loves the 3.92 for towing!!

 

[pacofortacos]

Also, with 3.92 gears the engine RPMs are much higher shifting through the gears from a dead stop, tell with the higher RPMs are you consuming more fuel, and are these higher RPM's good for the engine? I know everyone loves the 3.92 for towing!!

Not sure about this as the computer controls the shift points. I tend to find almost all engines if driven the same way shift at about the same rpm for me - V8, V6 it doesn't really matter. Most shifting is done aroung 1800-2100 rpms for how I drive.

 

[Cableman]

Just did a smokey mountain run, over 2k miles, 392s and 305/55-20s, 4 people and bed loaded.
1st tank was 19mpg, second 17 which led me through the mountains. Reset evic on way home and it displayed 20.3mpg. Evic on way down was actually a hair lower then my calculation!
Nice having the 32gal tank and only having to refuel about ¾ way down, the most i was able to put back into this tank was 27 and thats with evic telling me theres 20 miles left which obviously there must be a lot more.

 

[Jeepwalker]

Just did a smokey mountain run, over 2k miles, 392s and 305/55-20s, 4 people and bed loaded.
1st tank was 19mpg, second 17 which led me through the mountains. Reset evic on way home and it displayed 20.3mpg. Evic on way down was actually a hair lower then my calculation!

All of that was hand calculated?

 

[CheechDogg.0n37s]

Just did a smokey mountain run, over 2k miles, 392s and 305/55-20s, 4 people and bed loaded.
1st tank was 19mpg, second 17 which led me through the mountains. Reset evic on way home and it displayed 20.3mpg. Evic on way down was actually a hair lower then my calculation!
Nice having the 32gal tank and only having to refuel about ¾ way down, the most i was able to put back into this tank was 27 and thats with evic telling me theres 20 miles left which obviously there must be a lot more.

Nice .... I am getting 13-15 in town and on long trips up to 20 with 37s with the 4.88s ...

Honestly if you drive wanting the most mpgs you can best it with any car/truck set up you have if you drive like you should .... I can easily get 17 mpg in town but I love to have fun with my truck when I drive it ,,,

The 3.21s on my truck were a lot of fun while I had it stock, I was getting 18 in town and hardly drove it on the freeway lol ... when I lifted it that's when I started driving it everywhere lol ..

But those numbers are what I would be satisfied with my driving style and habits ....good stuff

 

[670hoth]

I have a 2017 quad cab hemi with stock 275-60R20s and 3.92 gears. At 75 mph it tachs 2100 RPM. I often do an approximately 200 mile run for work that's about 50% interstate which I drive around 75 mph and 50% back roads ranging from 45 to 60 and through a few towns and stop light/signs. I can get 21 miles a gallon on this run. I don't think that's bad since I can tow 10,000 pounds if I want to.

 

[ramffml]

I don't think that's bad since I can tow 10,000 pounds if I want to.

The 3.21 can tow just as much as the 3.92. It just means that if both trucks are stopped and then floor it, the 3.21 will take a little longer to hit 20 mph but beyond that both trucks have the same gears available. Both trucks will feel just as strong pulling up a mountain, or passing a semi on the freeway.

Tow capacity numbers are really marketing numbers. My truck is "rated" to tow about 8500 or thereabouts, but nothing wrong happens if I tow 10,000 instead.

The real number that matters, is payload. That's an engineered number based on rear axle ratings and suspension, and both trucks are identical here. The simple truth is, based on travel trailer tongue weights of 10 to 15 percent, neither your truck or mine can actually pull more than 8500 without exceeding payload.

So no, in most cases you can't really pull 10,000 pounds without exceeding the most import limitation of your truck: payload.

 

[Cableman]

All of that was hand calculated?

Pretty much, The drive down was hand calculated, the way back up just hand calculated 1st tank which was 18.6